Well, it kind of worked. When I set Code cleanup on save to Never. It creates two styles, let say:
<img style="border: 1px solid black; float: left; margin-right: 10px; margin-bottom: 10px;" mce_style="border: 1px solid black; float: left; margin-right: 10px; margin-bottom: 10px;" src="images/stories/tecnicos/german_gonzalez/basilico_02.jpg" mce_src="images/stories/tecnicos/german_gonzalez/basilico_02.jpg" alt="Germán González" title="Germán González">
This causes problems with RokStories since it won't create the thumbnails for the images. It also will convert all the strong tags into b tags ...
I suppose this is an integration issue. If I try the editor on one of the examples (at TinyMCE home page), when using bold it puts strong and doesn't create mce_style when styling the image.